:sig
String memcache_get(u64 connection, String key, String default_value = "")

:params
connection : connection handle
key : key string
default_value : optional default value
return value : value that was returned by the Memcache server

:see
>memcache

:content
Retrieves a value from an existing Memcache connection.

If the key is missing, `default_value` is returned instead.

:example
u64 conn = memcache_connect();
if(conn != 0) { memcache_set(conn, "doc_get_key", "stored value"); print(memcache_get(conn, "doc_get_key"), "\n"); }
else print("(requires a reachable memcached server)\n");